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Any word on the whole DDR4/One DIMM per channel thing? All the specs I can find say that DDR4 only supports one, but most of the X79 motherboards we're seeing seem to have two. Perhaps it's backwards-compatible with DDR3?Reply

i doubt they are backwards compatible as they are a completely different pin count (280 vs 288)i think they changed the spec of ddr3 to allow more than one dimm - some xeon motherboards even had 3 dimms per channelReply

I've also heard this, but I just can't wrap my head around it. I'm guessing something was lost in translation through the rumor mill. DDR4 being limited to a single DIMM per channel would be ridiculous and incredibly restrictive, especially in the server/enterprise markets. I think it's more likely that all the X99 boards we've seen thus far is proof that DDR4 is not limited to a single DIMM per channel.Reply

DDR4 is point-to-point like FB-DIMMs. Going to more than one DIMM per channel requires either registered or load reduced DIMMs from my understanding. Unbuffered memory is limited to 1 DIMM per channel.

Wow, that sounds pretty ridiculous, at least from a price and performance perspective. If that's the case clearly DDR4 has been catered to server/enterprise environments. From my limited understanding of FB-DIMMs, registers have a negative impact on performance, and increase complexity and thus costs per DIMM. Am I reading this wrong? Why would JEDEC chose to go that route for a memory specification intended for wide adoption in consumer systems, where multi-DIMMs per channel has long since become the norm?Reply

It's probably due to pcie lanes not being available for that number of ports while still enabling all the other features. It's a smart decision too, because you have many devices you might hook up that have no need for usb3, like keyboards and mice. Reply

The chipset is limited to 6 native USB 3.0 ports, but like 14 USB 2.0 ports (noting that every used 3.0 port also takes up a 2.0 port). So all those additional 2.0 ports come for free but you need additional PCIe controllers if you want more 3.0 ports.Reply